What is the size of the matrix resulting from...

1 x 3

Step-by-step explanation:

The order of the first matrix is 1 × 3

The order of the second matrix is 3 × 3

that is (1 × 3 ) × (3 × 3 )

The bold values at the ends of the orders give the order of the product, that is

1 × 3

given that triangle abc is transformed two times to get triangle

a"b"c"

first abc is transformed in to a'b'c' as follows:

the coordinates of a are (1,-1) and transformed into a'(-1,1)

similarly b (4,-2) became b'(-4,2) and

c(7,-2) became c'(-7,2)

i.e. (x,y) becomes (-x,-y)

this is nothing but reflection about a point here origin.

thus first transformation is reflection on the origin.

next is exactly shifting 3 units down

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